User2529 - 9 months ago 42

C++ Question

as the question shows, I need to use bubble sort to sort a 2 dimensional array. This should work for any N*M array.

I know we are not supposed to ask questions without attempting anything first. But I am on a very tight schedule and I'm learning c++ now. I couldn't find any links with suitable information to code this.

If someone could help me with this, it'd be great

Answer

You can cast pointer to the first row of a two-dimensional array to pointer to int and sort the array as a one-dimensional array.

Here you are

```
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <ctime>
void bubble_sort( int *a, size_t n )
{
for ( size_t last = n; !( n < 2 ); n = last )
{
last = 1;
for ( size_t i = 1; i < n; i++ )
{
if ( a[i] < a[i-1] )
{
std::swap( a[i], a[i-1] );
last = i;
}
}
}
}
int main()
{
const size_t N = 3;
const size_t M = 4;
int a[N][M];
std::srand( ( unsigned int )std::time( nullptr ) );
for ( size_t i = 0; i < N; i++ )
{
for ( size_t j = 0; j < M; j++ ) a[i][j] = std::rand() % ( M * N );
}
for ( size_t i = 0; i < N; i++ )
{
for ( size_t j = 0; j < M; j++ )
{
std::cout << std::setw( 2 ) << a[i][j] << ' ';
}
std::cout << std::endl;
}
std::cout << std::endl;
bubble_sort( reinterpret_cast<int *>( a ), N * M );
for ( size_t i = 0; i < N; i++ )
{
for ( size_t j = 0; j < M; j++ )
{
std::cout << std::setw( 2 ) << a[i][j] << ' ';
}
std::cout << std::endl;
}
return 0;
}
```

The program output might look like

```
7 3 8 7
6 8 5 0
10 9 9 3
0 3 3 5
6 7 7 8
8 9 9 10
```

Source (Stackoverflow)